Please excuse my indulgence! I hope this is actually useful.
Zebra has probably the most complexity under the hood - that's to say the filters, for example, are not just filters, they're multiple tuned stages of saturation and filtering (visibly so in the XMF modules) in order to achieve a very rich and complex behavior and sound, which some might call "analog". In Phase Plant, you're responsible for building that complexity with bare tools. Case in point again, Zebra offers 4-5 comb filter types per comb module, with different arrangements of multiple processors within the feedback path, leading to an impossibly large sonic palette for physical modelling and creating shimmering, groaning, airy, metallic sounds, the list goes on. Phase Plant by contrast offers a comb filter with a feedback control, but Phase Plant has a different idea in mind when it comes to architecture.
Pigments is sort of an intermediary. Its layout is strict; it is not nearly so semi-modular, but the modules it contains are often somewhat more complex than in Phase Plant. For example, it offers an allpass filter in the feedback path of its Comb LPF - which is a useful and customizable sound (weird and pretty). Pigments' additive is not mirrored in any way by the other two synths, mostly producing harsh or "additive-sounding" sounds, but the parameterization affords making a variety of useful and pleasing sounds - it is worth a few tries. Pigments' granular is uniquely good in that it does not shorten grain length past certain grain rates/densities, leading to more capability for the "wash" sound and being able to sear a steak with your CPU. The effects, like the shimmer reverb, delay and chorus sound good! The modulation is comparatively limited, which is probably enough for most users, evidenced by a whole lot of good-sounding presets.
The extent to which you can process sounds in Kilohearts plugins, and the ease and speed of making such complex patches, is the selling point for Phase Plant. Right off the bat you've got as many or more features for oscillator types, fx and modulation (so many more). But then you can go running 49 parallel keytracked polyphonic resonators in a Snap Heap setup, with macros and modulators augmenting their tuning, decay, panning etc.; which might sound alarming, but Phase Plant makes it easy. And you could make it two million resonators or more if your cpu was designed by the Lord; the system scales as far as you and your cpu can take it. On the Kilohearts discord you can find ample Snap Heap presets that will with a few macro knobs completely transform any input sound into something completely different, maybe beautiful, or a complete mess. That's the power of Snap Heap and the Khs modulation system! Doing that, and having one of the most powerful modulation/polyphonic FX/FM implementations in softsynths, and the layering and unison modes, that's why Phase Plant is special.
At which point one might wonder why not just get Falcon or MSoundFactory -- answer being they kind of suck to use compared to Phase Plant or Zebra. For most people, anyway - they're certainly more powerful in some ways. Phase Plant is powerful enough that the 8 macros at the top may as well be replaced soon with the Performance View of these Kontakt-competitor super-synths, and maybe at some point they will. Phase Plant is after all more likely to get a multisampling system and custom feedback chain processing/routing than Falcon or MSoundFactory are to get a workflow that doesn't make one want to leave their studio! Sad as it is. In fact, those features already being talked about by the devs. So it is not hyperbole. :|
, or well enough anyway. I understand what Kilohearts is saying when they talk about being happy with the sound and I know what you mean when you say you're not...
